Daily Report #4818
- From: "Cooper, Joe" <jcooper@xxxxxxxxxxxx>
- Date: Wed, 25 Mar 2009 07:40:00 -0700
HUBBLE SPACE TELESCOPE - Continuing to collect World Class Science
DAILY REPORT #4818
PERIOD COVERED: 5am March 24 - 5am March 25, 2009 (DOY
083/0900z-084/0900z)
OBSERVATIONS SCHEDULED
ACS/SBC 11980
Deep FUV Imaging of Cooling Flow Clusters
We propose to take deep ACS FUV images of a carefully selected sample
of 19 bright central galaxies in nearby galaxy clusters. This program
is the last critical element of a comprehensive investigation of the
impact of stellar and AGN feedback on the local galaxy cluster
environment. The HST images will complement new, high-resolution,
Halpha images obtained with the recently commissioned
Maryland-Magellan Tunable Filter (MMTF) on the Baade 6.5m telescope,
archival Chandra, VLA, and GALEX data, and on-going H2/NIR
observations. The MMTF data have revealed unsuspected filamentary
complexes in several systems. The GALEX data often show hints of
extended NUV and FUV emission on a similar scale, but their poor
spatial resolution prevents meaningful comparison with the MMTF data.
The HST data will provide this much needed gain in resolution. The
combined radio-H2-Halpha-FUV-X-ray dataset will allow us to derive
with unprecedented precision the role of the AGN, hot stars, shocks,
and relativistic particles on the excitation and thermodynamics of the
multi-phase intracluster and interstellar media in these systems. This
is an important question since the formation and evolution of most
cluster galaxies have likely been affected by these processes.
FGS 11788
The Architecture of Exoplanetary Systems
Are all planetary systems coplanar? Concordance cosmogony makes that
prediction. It is, however, a prediction of extrasolar planetary
system architecture as yet untested by direct observation for main
sequence stars other than the Sun. To provide such a test, we propose
to carry out FGS astrometric studies on four stars hosting seven
companions. Our understanding of the planet formation process will
grow as we match not only system architecture, but formed planet mass
and true distance from the primary with host star characteristics for
a wide variety of host stars and exoplanet masses.
We propose that a series of FGS astrometric observations with
demonstrated 1 millisecond of arc per-observation precision can
establish the degree of coplanarity and component true masses for four
extrasolar systems: HD 202206 (brown dwarf+planet); HD 128311
(planet+planet), HD 160691 = mu Arae (planet+planet), and HD 222404AB
= gamma Cephei (planet+star). In each case the companion is identified
as such by assuming that the minimum mass is the actual mass. For the
last target, a known stellar binary system, the companion orbit is
stable only if coplanar with the AB binary orbit.
WFPC2 11975
UV Light from Old Stellar Populations: a Census of UV Sources in
Galactic Globular Clusters
In spite of the fact that HST has been the only operative
high-resolution eye in the UV-window over the last 18 years, no
homogeneous UV survey of Galactic globular clusters (GGCs) has been
performed to date. In order to fill this gap in the stellar population
studies, we propose a program that exploits the unique capability of
the WFPC2 and the SBC in the far-/mid- UV for securing deep UV imaging
of 46 GGCs. The proposed observations will allow to study with
unprecedented accuracy the hottest GGC stars, comprising the extreme
horizontal branch (HB) stars and their progeny (the so-called
AGB-manque', and Post-early AGB stars), and "exotic stellar
populations" like the blue straggler stars and the interacting
binaries. The targets have been selected to properly sample the GGC
metallicity/structural parameter space, thus to unveil any possible
correlation between the properties of the hot stellar populations and
the cluster characteristics. In addition, most of the targets have
extended HB "blue tails", that can be properly studied only by means
of deep UV observations, especially in the far-UV filters like the
F160BW, that is not foreseen on the WFC3. This data base is
complemented with GALEX observations in the cluster outermost regions,
thus allowing to investigate any possible trend of the UV-bright
stellar types over the entire radial extension of the clusters.
Although the hottest GGC stars are just a small class of "special"
objects, their study has a broad relevance in the context of structure
formation and chemical evolution in the early Universe, bringing
precious information on the basic star formation processes and the
origin of blue light from galaxies. Indeed, the proposed observations
will provide the community with an unprecedented data set suitable for
addressing a number of still open astrophysical questions, ranging
from the main drivers of the HB morphology and the mass loss
processes, to the origin of the UV upturn in elliptical galaxies, the
dating of distant systems from integrated light, and the complex
interplay between stellar evolution and dynamics in dense stellar
aggregates. In the spirit of constructing a community resource, we
entirely waive the proprietary period for these observations.
WFPC2 11986
Completing HST's Local Volume Legacy
Nearby galaxies offer one of the few laboratories within which stellar
populations can be tied to multi-wavelength observations. They are
thus essential for calibrating and interpreting key astrophysical
observables, such as broad-band luminosities, durations and energy
input from starbursts, and timescales of UV, H-alpha, and FIR
emission. The study of stellar populations in nearby galaxies requires
high-resolution observations with HST, but HST's legacy for this
limited set of galaxies remains incomplete.
As a first attempt to establish this legacy, The ACS Nearby Galaxy
Survey Treasury (ANGST) began observations in late 2006. ANGST was
designed to carry out a uniform multi-color survey of a volume-limited
sample of ~70 nearby galaxies that could be used for systematic
studies of resolved stellar populations. The resulting data provide
nuanced constraints on the processes which govern star formation and
galaxy evolution, for a well-defined population of galaxies. All
photometry for the survey has been publicly released.
However, the failure of ACS 4.5 months after ANGST began taking data
led to a drastic reduction in the planned survey. The loss is
two-fold. First, the goals of completeness and uniformity were greatly
compromised, impacting global comparison studies. Second, the variety
of observed star formation histories was reduced. Given that we have
never found two galaxies with identical star formation histories, and
fully sampling the population allows us to catch those few systems
whose star formation rates and metallicities place the strongest
constraints on key astrophysical processes.
Here we propose WFPC2 observations of all remaining galaxies within
the Local Volume (D<3.5Mpc) for which current HST observations are
insufficient for meaningful stellar population studies. We will use
these observations for research on the star formation histories of
individual galaxies and the Local Volume, detailed calibrations of
star formation rate indicators, and the durations of starbursts. We
will also make them publicly available through the ANGST archive to
support future research. The proposed observations will finally
complete a lasting legacy of HST
FLIGHT OPERATIONS SUMMARY:
Significant Spacecraft Anomalies: (The following are preliminary
reports of potential non-nominal performance that will be
investigated.)
HSTARS: (None)
COMPLETED OPS REQUEST: (None)
COMPLETED OPS NOTES: (None)
SCHEDULED SUCCESSFUL
FGS GSAcq 05 05
FGS REAcq 10 10
OBAD with Maneuver 30 30
SIGNIFICANT EVENTS: (None)
.
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